diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirBuilderInferenceSession.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirBuilderInferenceSession.kt
index d4a1bfead0c..13fb95a2cb5 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirBuilderInferenceSession.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirBuilderInferenceSession.kt
@@ -155,9 +155,8 @@ class FirBuilderInferenceSession(
         val commonSystem = components.session.inferenceComponents.createConstraintSystem()
         val nonFixedToVariablesSubstitutor = createNonFixedTypeToVariableSubstitutor()
 
-        integrateConstraints(commonSystem, initialStorage, nonFixedToVariablesSubstitutor, false)
-
-        var effectivelyEmptyCommonSystem = true
+        var effectivelyEmptyCommonSystem =
+            !integrateConstraints(commonSystem, initialStorage, nonFixedToVariablesSubstitutor, false)
 
         for ((_, candidate) in commonCalls) {
             val hasConstraints =
diff --git a/compiler/testData/diagnostics/testsWithStdLib/builderInference/inferenceFromLambdaReturnType.fir.txt b/compiler/testData/diagnostics/testsWithStdLib/builderInference/inferenceFromLambdaReturnType.fir.txt
index a89a3e3de8f..2db4b64a06b 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/builderInference/inferenceFromLambdaReturnType.fir.txt
+++ b/compiler/testData/diagnostics/testsWithStdLib/builderInference/inferenceFromLambdaReturnType.fir.txt
@@ -8,7 +8,7 @@ FILE: inferenceFromLambdaReturnType.kt
     public final fun <S> getWithFallback(fallback: R|(ThemeKey<S>) -> S|): R|kotlin/Unit| {
     }
     public final fun main(): R|kotlin/Unit| {
-        R|/getWithFallback|<R|kotlin/String|>(<L> = getWithFallback@fun <anonymous>(it: R|ThemeKey<ERROR CLASS: Type for S is not inferred>|): R|kotlin/String| <inline=NoInline>  {
+        R|/getWithFallback|<R|kotlin/String|>(<L> = getWithFallback@fun <anonymous>(it: R|ThemeKey<kotlin/String>|): R|kotlin/String| <inline=NoInline>  {
             ^ String()
         }
         )